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Chemical synthesis of graphene for dye solar cells electrodes

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Chemical synthesis of graphene for dye solar cells electrodes
CHEMICAL SYNTHESIS OF
GRAPHENE FOR DYE SOLAR
CELLS ELECTRODES
Presenter: F. T. Thema
Name of presentation
Organisation name
Overview
• Introduction
• Aim and Objectives
• Production of graphene
• Graphene oxide film preparation
• Morphological properties of GO
• Spectroscopy of GO
• Conclusion
• Future work
• Acknowledgements
• References
Introduction
Graphene Superlatives
Thinnest imaginable material largest surface area
(2.700 m2 per gram)
Strongest material ever measured (theoretical
limit)
Stiffness known material (stiffer than diamond)
Most stretchable crystal (up to 20 % elasticity)
Record thermal conductivity (outperforming
diamond)
Highest current density at room T (106 times of
copper)
Completely impermeable (even He atoms cannot
squeeze through)
Aim and Objectives
Aim:
• To use the unusual and unique properties of
graphene as transparent and conductive electrode to
be used as TCO equivalent.
Objectives:
• Use modified Hummer’s method to
synthesize/engineer large graphene thin films with
different properties (3-5 nm)
• Use reduced graphene oxide in solar cells
Production of graphene
Methods of producing graphene
• K.S. Novoselov et al Nature 2012,
490, 192–200
K.S. Novoselov et al Nature 2012, 490, 192–200
Graphene Oxide Film
Preparation
Graphite Flakes
GO suspension in water
Morphological Properties of GO
e-
Conductive
Optical Microscopy
Scanning Electron Microscopy
Raman characterization of GO
and rGO
Intensity a.u.
GO
r-GO (Anealing)
r-GO (Our Method)
500
1000
1500
2000
Raman Shift cm
Material
ID/IG
GO
1.2
r-GO (Annealing)
0.95
r-GO (Our Method)
0.96
2500
-1
3000
Conclusion
• Graphene oxide solution was produced
• Vacuum filtration was used to produce large area
graphene oxide films
• The graphene oxide was reduced to produce
graphene with suitable properties for use as a TCO
Future work
• Use different methods to reduce graphene oxide to
graphene
• Use the large area graphene films as transparent
conductors in solar photovoltaic devices
Acknowledgements
• iThemba LABS
• Unisa
• Philip - iThemba LABS Radiobiology
• Stephen Nzioki & B , Dr F. Cumings & B. Sone – UWC
• Chris B – iThemba LABS
• Takalani Madima - Unisa
• G Bepete & N.J. Coville – WITS University
Related publications
•
F.T. Thema et.al Synthesis and characterization of graphene thin films by chemical
reduction exfoliated and intercalated graphite oxide. J. Chem. (2013) DOI:
10.1155/2013/150536.
•
F.T. Thema et al Synthesis and characterization of graphene thin films via
Hummers Method. Technical Proceedings of the Nano Science and Technology
Institute, (2012) 1, 13-16. ISBN 678-1-4665-6274-5.
•
Ezekiel D. Dikio, Force T. Thema et. al One-step reduction, characterization and
magnetic behaviour of exfoliated graphene oxide. J. Mater. Sci. Pol. (2012) DOI:
10.2478/s13536-012-0068-2.
•
Abdullahi M. Farah, Force T. Thema et.al Electrochemical detection of hydrogen
peroxide based on graphene oxide/Prussian blue modified glassy carbon electrode.
Int. J. Electrochem. Sci. 7(6) (2012) 5069 – 5083.
•
E.D. Dikio, F.T. Thema, et. al Synthesis of carbon nanotubes by catalytic
decomposition of ethane using Co-Zn-Al catalyst. Inter. J. Nanotech Appl, vol 4, 2
(2010) 117-124.
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